. >> you bet. >>> in this week's office politics, we talk with nbc without correspondent kristen welker. kristen spent last year on the obama campaign trail and talks about the moment she knew the president was headed to victory. i began by talking to her about the challenges of living on the road for months. >> it was a challenge, but it was so thrilling. i'd always wanted to cover a campaign at the national level. so i woke up and i was excited every day. it was just a thrill to literally watch history unfold and to be a part of that. the biggest challenge was that it was exhausting, and there was a physical toll, which i wasn't prepared for. i wasn't prepared for getting sick on the campaign trail. it's not easy to just call up your doctor and say, hey, i'm not feeling well. you have to literally do a lot of improvisation and, remember, you're eating sort of what's put in front of you. when you're on the campaign trail, 90% of the food is a carbohydrate. so that's a big challenge. especially someone like myself, who likes to be healthful and exercise a lot. exercising goes out the wi